Megakaryocytes are large bone marrow cells responsible for producing platelets, which are essential for blood clotting. They develop from hematopoietic stem cells and undergo a process called endomitosis, where they replicate their DNA without dividing, resulting in a large cell with multiple nuclei. Once mature, megakaryocytes extend long projections called proplatelets into the bloodstream. These proplatelets fragment into smaller pieces, forming platelets that circulate in the blood. Platelets play a crucial role in wound healing and maintaining hemostasis, preventing excessive bleeding when injuries occur.